If you have a heatstick this method works like a charm. Put the bottles in a bucket and heat up the water with a heatstick. Periodically check to see when the labels are falling off. You don't have to bring the water to a complete boil but it doesn't hurt. My friends never rinse the bottles they give to me so this method also helps dislodge the crap growing inside the bottles and makes them easier to clean. Let the bucket sit overnight or add water to bring the temp down before handling. A 12 pack fits perfect in a bucket.

second. i just keep a bucket in the garage with oxyclean solution and drop the bottles in after they are empty. When the bucket is full, i just pull them out and rinse them. Takes VERY little effort if you keep a dedicated bucket.